(a) Field of the Invention
The present invention relates to an ink jet recording process, in particular to an ink jet recording process devised so that an aqueous ink circulating within an ink jet printer is brought into contact with an ion-exchange resin and thus recording is ensured for a long period of time without causing clogging of ink at a narrow nozzle (the fore end portion of an ink jet head).
(b) Description of the Prior Art
The so-called ink jet recording process, which comprises jetting a liquid ink (a water-soluble dye-containing ink for use in ink jet recording) through a narrow nozzle (namely, a discharge nozzle) so as to have ink particles charged while flying about, and attaching said ink particles selectively on the surface of a given recording paper (paper to be recorded) using a control electrode, has been put to practical use in the field of facsimile machines, the output printers of electronic calculators and the like.
This ink jet recording process is surely advantageous in the points: (1) high speed recording is possible, (2) the object to be recorded can include various articles such as common paper, plastic sheet, cloth and others, (3) color recording is possible, and so forth, but on the other hand it is defective in that a complete counterplan has not been considered yet for overcoming the clogging phenomenon of the narrow nozzle and consequently long-run recording can not be ensured.
Specifically, when this ink jet recording system is run for a long period of time such as 1000 hours or more or is stopped for a long period of time, there occurs clogging of ink at the fore end of the narrow nozzle so that the direction and quantity of ink jetted become unstable and further the size and flying speed of ink drops (ink particles) vary exceedingly, whereby it becomes impossible to obtain a clear-cut record and jet printing is hampered according to circumstances.
It is known to provide a plurality of small-mesh filters in the ink circulation system for the purpose of preventing the above mentioned clogging at the narrow nozzle portion (Japanese Patent Publication No. 19746/1980). However, this design encounters another problem that the filters clog so as to shorten their lives. The use of a composite filter, which comprises placing a surface filter and a depth filter one over the other, can somewhat prolong the filter's life but there is a limit in this. Accordingly, this means should be said insufficient to work out a substantial solution to said problem.
Japanese Laid Open Patent Application No. 85804/1976 has proposed a method of preventing the occurrence of clogging at the narrow nozzle portion which comprises incorporating a chelating reagent in ink so as to dissolve the metallic compounds present in the ink. But, this brings about an undesirable situation that said chelating reagent-containing ink contacts with metal parts of the ink circulating system, thereby accelerating corrosion of said metal parts.
Further, Japanese Laid Open Patent Application No. 120007/1979 has proposed an expedient of further adding a rust preventive to the chelating reagent-containing ink so as to prevent corrosion of the above mentioned metal parts. However, this expedient is surely serviceable for preventing the corrosion of said metal parts merely to some degree, but still has a limit in the prevention of corrosion. Accordingly, this should also be said insufficient to provide a substantial solution thereto. In addition, this expedient can be observed to include such a disadvantage that when the ink jet recording system is stopped for a long period of time, the rust preventive precipitates and deposits at the fore end portion of the nozzle, whereby the jetting direction of ink is sometimes changed widely.